[ASP.NET] asp.net mvc with the Length=5 parameter

        //
        Summary:
        Write the <form> start tag to the response.
        //
        Parameters:
        //   ajaxHelper:
        AJAX helper.
        //
        //   actionName:
        The name of the action method that will process the request.
        //
        //   controllerName:
        The name of the controller.
        //
        //   routeValues:
        An object that contains routing parameters. Retrieve parameters using reflections by examining the properties of the object. This object is usually created using the object initialization syntax.
        //
        //   ajaxOptions:
        Objects that provide asynchronous request options.
        //
        //   htmlAttributes:
        An object that contains the HTML properties to be set for that element.
        //
        Return results:
        <form> Start tagging.
        public static MvcForm BeginForm(this AjaxHelper ajaxHelper, string actionName, string controllerName, object routeValues, AjaxOptions ajaxOptions, object htmlAttributes);